Field of the Invention
The present invention relates to a liquid ejection head to be mounted on a liquid ejection apparatus, the liquid ejection apparatus and a manufacturing method for the liquid ejection head.
Description of the Related Art
In the liquid ejection head configured to eject liquid through an ejection port, in general, a recovering operation for removing a thickening substance of the liquid (also, referred to as ink) and accumulated air bubbles in the liquid ejection head by suctioning the thickening substance and the air bubbles through the ejection port is performed in order to maintain a favorable ejection state. On this occasion, the ink which is contained in a liquid chamber in the liquid ejection head is also suctioned and discharged from the ejection port in order to surely discharge the thickening substance and the accumulated air bubbles.
In a liquid ejection head used in a printing apparatus, there exists a liquid ejection head for large size printing which is adapted for large size printing by increasing the number of the ejection ports. The amount of the ink to be discharged in the recovering operation is increased with increasing the number of the ejection ports. Therefore, it is necessary to contain much ink by increasing the capacity of the liquid chamber of the liquid ejection head.
On the other hand, also the number of the air bubbles generated during a printing operation is inevitably increased with increasing the number of the ejection ports. Since some of the air bubbles are accumulated in the liquid chamber, it is necessary to increase the capacity of the liquid chamber also in order to accumulate a certain amount of the generated air bubbles in the liquid chamber. It becomes possible to reduce the number of the recovering operations by the liquid chamber which has the capacity sufficient for accumulation of the air bubbles.
In Japanese Patent Laid-Open No. 2002-307709, two liquid chambers, that is, a first liquid chamber and a second liquid chamber are arranged in a liquid ejection head, with a filter interposed therebetween for preventing foreign matters in the ink and the air bubbles from entering the ejection port, and a liquid chamber groove structure is provided in the second liquid chamber located on the ejection port side so as to enable communication of the liquid between the first liquid chamber and the second liquid chamber with the filter being interposed therebetween.
In general, in a serial scan type liquid ejection head, an ejection element substrate which includes the ejection port for ejecting the ink is configured compactly for cost saving. Therefore, the liquid chamber which is provided in a flow passage which supplies the liquid to the election element substrate is configured such that the width in a scanning direction is gradually narrowed as it approaches the ejection port. Thereby, it becomes possible to further narrow down a scanning range of the liquid ejection head relative to a scanning-direction width of a printing medium and higher speed printing becomes possible.
Accordingly, in order to achieve both of high speed printing and a reduction in number of the recovering operations, it is necessary to narrow the scanning-direction width of the liquid chamber while increasing the capacity of the liquid chamber in the liquid ejection head. Therefore, it is demanded to configure the liquid chamber so as to be large in a height direction.
Here, in general, a housing which configures the liquid chamber in Japanese Patent Laid-Open No. 2002-307709 is fabricated by molding. A liquid chamber groove structure of the second liquid chamber in FIG. 10 in Japanese Patent Laid-Open No. 2002-307709 is formed by a die to be removed toward the filter side after molding. It is necessary to provide a draft angle to the die. However, in a case where the draft angle is provided to the liquid chamber groove structure leads, a width of a groove on the ejection port side becomes narrower than a width of the groove on the filter side.
In a case where the liquid chamber is to be configured to be narrow in the scanning direction and to be large in the height direction, it is necessary to set meniscus force of the groove higher, that is, to set the width of the groove narrow. However, in a case where the liquid chamber is made large in the height direction in a configuration which includes the liquid chamber groove structure in Japanese Patent Laid-Open No. 2002-307709, the groove on the ejection port side becomes too narrow due to provision of the draft angle and thus it becomes difficult to provide the draft angle. Accordingly, in the configuration in Japanese Patent Laid-Open No. 2002-307709, although high speed printing is possible, it becomes difficult to make the liquid chamber large in the height direction and therefore it becomes also difficult to reduce the number of the recovering operations.